A:She is a good teacher.
B:They are teachers.
C:He is a good teacher.
如图表示种群的各个特征之间的关系,下列叙述正确的是( )
— Give me a pencil, please.
— ________.
“自古书契多编以竹简,其用缣(细绢)帛者谓之为纸。缣贵而简重,并不便于人。伦乃造意,用树肤、麻头及敝布、鱼网以为纸。”这主要说明了